Improving the technology that is available for determining the geographic location of user equipment, such as cellular phones, inside buildings has been an important area for research and even more so responsive to new initiatives by the Federal Communications Commission (FCC) in the United States. GPS provides accurate location services while a GPS enabled user equipment has an unobstructed view of the sky. However, GPS signals are very faint and cannot usually be received indoors or when obstructed in outdoor urban areas.
The present location determination systems used for emergency calling has been determined in some circumstances to fail during more than 50% of e911 calls originated from user equipment inside buildings. The FCC has therefore asked the telecommunications industry to provide improved terrestrial positioning systems. New proposed positioning systems include NextNav's system that uses powerful terrestrially-based transmitters to transmit very precise timed signal and information over a GPS-like channel about the geographic location of the transmitters. However, these systems will require significant investment to deploy new infrastructure.
The FCC, other governmental agencies, and wireless operators are concerned about possible third party manipulation of the geographical location reported during an e911 call. User equipment are only allowed to report actual raw data from GPS signals and cell tower positioning signals to the positioning infrastructure where all calculations and geographical positioning estimation is performed.
The FCC has proposed using Wi-Fi Access points and Bluetooth beacons for indoor positioning. One such approach develops a central database of known locations of Wi-Fi access points which is used to determine the location of user equipment which have reported in an emergency call; identifiers of local Wi-Fi access points, and corresponding radio link parameters. However, Wi-Fi access points are inherently mobile which further heightens concern about third party manipulation of the geographical location determined during an emergency call.